#include<stdio.h>
void main()
{
    int x,y;
    printf("请输入自变量x:");
    scanf("%d",&x);
    if(x<6)
{
    y=x-12;
    printf("x=%d,y=%d\n",x,y);
}
else if(x<15)
{
    y=3*x-1;
    printf("x=%d,y=%d\n",x,y);
}
else
{
    y=5*x+9;
    printf("x=%d,y=%d\n",x,y);
}
return 0;
}